/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.catalina.valves;

import java.io.IOException;
import java.io.StringReader;
import java.net.InetAddress;
import java.net.URLEncoder;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.TimeZone;

import javax.servlet.http.Cookie;
import javax.servlet.http.HttpSession;

import org.apache.catalina.Lifecycle;
import org.apache.catalina.connector.Request;
import org.apache.catalina.connector.Response;
import org.apache.catalina.util.ServerInfo;
import org.apache.juli.logging.Log;
import org.apache.juli.logging.LogFactory;

/**
 * An implementation of the W3c Extended Log File Format. See
 * http://www.w3.org/TR/WD-logfile.html for more information about the format.
 * 
 * The following fields are supported:
 * <ul>
 * <li><code>c-dns</code>: Client hostname</li>
 * <li><code>c-ip</code>: Client ip address</li>
 * <li><code>bytes</code>: bytes served</li>
 * <li><code>cs-method</code>: request method</li>
 * <li><code>cs-uri</code>: The full uri requested</li>
 * <li><code>cs-uri-query</code>: The query string</li>
 * <li><code>cs-uri-stem</code>: The uri without query string</li>
 * <li><code>date</code>: The date in yyyy-mm-dd format for GMT</li>
 * <li><code>s-dns</code>: The server dns entry </li>
 * <li><code>s-ip</code>: The server ip address</li>
 * <li><code>cs(XXX)</code>: The value of header XXX from client to server</li>
 * <li><code>sc(XXX)</code>: The value of header XXX from server to client
 * </li>
 * <li><code>sc-status</code>: The status code</li>
 * <li><code>time</code>: Time the request was served</li>
 * <li><code>time-taken</code>: Time (in seconds) taken to serve the request</li>
 * <li><code>x-A(XXX)</code>: Pull XXX attribute from the servlet context
 * </li>
 * <li><code>x-C(XXX)</code>: Pull the first cookie of the name XXX </li>
 * <li><code>x-O(XXX)</code>: Pull the all response header values XXX </li>
 * <li><code>x-R(XXX)</code>: Pull XXX attribute from the servlet request
 * </li>
 * <li><code>x-S(XXX)</code>: Pull XXX attribute from the session </li>
 * <li><code>x-P(...)</code>: Call request.getParameter(...) and URLencode
 * it. Helpful to capture certain POST parameters. </li>
 * <li>For any of the x-H(...) the following method will be called from the
 * HttpServletRequestObject </li>
 * <li><code>x-H(authType)</code>: getAuthType </li>
 * <li><code>x-H(characterEncoding)</code>: getCharacterEncoding </li>
 * <li><code>x-H(contentLength)</code>: getContentLength </li>
 * <li><code>x-H(locale)</code>: getLocale</li>
 * <li><code>x-H(protocol)</code>: getProtocol </li>
 * <li><code>x-H(remoteUser)</code>: getRemoteUser</li>
 * <li><code>x-H(requestedSessionId)</code>: getGequestedSessionId</li>
 * <li><code>x-H(requestedSessionIdFromCookie)</code>:
 * isRequestedSessionIdFromCookie </li>
 * <li><code>x-H(requestedSessionIdValid)</code>: isRequestedSessionIdValid</li>
 * <li><code>x-H(scheme)</code>: getScheme</li>
 * <li><code>x-H(secure)</code>: isSecure</li>
 * </ul>
 * 
 * 
 * 
 * <p>
 * Log rotation can be on or off. This is dictated by the rotatable property.
 * </p>
 * 
 * <p>
 * For UvNIX users, another field called <code>checkExists</code>is also
 * available. If set to true, the log file's existence will be checked before
 * each logging. This way an external log rotator can move the file somewhere
 * and tomcat will start with a new file.
 * </p>
 * 
 * <p>
 * For JMX junkies, a public method called </code>rotate</code> has been made
 * available to allow you to tell this instance to move the existing log file to
 * somewhere else start writing a new log file.
 * </p>
 * 
 * <p>
 * Conditional logging is also supported. This can be done with the <code>condition</code>
 * property. If the value returned from ServletRequest.getAttribute(condition)
 * yields a non-null value. The logging will be skipped.
 * </p>
 * 
 * <p>
 * For extended attributes coming from a getAttribute() call, it is you
 * responsibility to ensure there are no newline or control characters.
 * </p>
 * 
 * 
 * @author Tim Funk
 * @author Peter Rossbach
 * 
 * @version $Revision: 633907 $ $Date: 2008-03-06 00:18:09 +0800 (星期四, 06 三月
 *          2008) $
 */

public class ExtendedAccessLogValve extends AccessLogValve implements Lifecycle {

	private static Log log = LogFactory.getLog(ExtendedAccessLogValve.class);

	// ----------------------------------------------------- Instance Variables

	/**
	 * The descriptive information about this implementation.
	 */
	protected static final String extendedAccessLogInfo = "org.apache.catalina.valves.ExtendedAccessLogValve/2.1";

	// ------------------------------------------------------------- Properties

	/**
	 * Return descriptive information about this implementation.
	 */
	public String getInfo() {
		return (extendedAccessLogInfo);
	}

	// --------------------------------------------------------- Public Methods

	// -------------------------------------------------------- Private Methods

	/**
	 * Wrap the incoming value into quotes and escape any inner quotes with
	 * double quotes.
	 * 
	 * @param value -
	 *            The value to wrap quotes around
	 * @return '-' if empty of null. Otherwise, toString() will be called on the
	 *         object and the value will be wrapped in quotes and any quotes
	 *         will be escaped with 2 sets of quotes.
	 */
	private String wrap(Object value) {
		String svalue;
		// Does the value contain a " ? If so must encode it
		if (value == null || "-".equals(value))
			return "-";

		try {
			svalue = value.toString();
			if ("".equals(svalue))
				return "-";
		} catch (Throwable e) {
			/* Log error */
			return "-";
		}

		/* Wrap all quotes in double quotes. */
		StringBuffer buffer = new StringBuffer(svalue.length() + 2);
		buffer.append('\'');
		int i = 0;
		while (i < svalue.length()) {
			int j = svalue.indexOf('\'', i);
			if (j == -1) {
				buffer.append(svalue.substring(i));
				i = svalue.length();
			} else {
				buffer.append(svalue.substring(i, j + 1));
				buffer.append('"');
				i = j + 2;
			}
		}

		buffer.append('\'');
		return buffer.toString();
	}

	/**
	 * Open the new log file for the date specified by <code>dateStamp</code>.
	 */
	protected synchronized void open() {
		super.open();
		if (currentLogFile.length() == 0) {
			writer.println("#Fields: " + pattern);
			writer.println("#Version: 2.0");
			writer.println("#Software: " + ServerInfo.getServerInfo());
		}
	}

	// ------------------------------------------------------ Lifecycle Methods

	protected class DateElement implements AccessLogElement {
		private Date currentDate = new Date(0);

		private String currentDateString = null;

		/**
		 * A date formatter to format a Date into a date in the format
		 * "yyyy-MM-dd".
		 */
		private SimpleDateFormat dateFormatter = new SimpleDateFormat(
				"yyyy-MM-dd");

		public DateElement() {
			dateFormatter.setTimeZone(TimeZone.getTimeZone("GMT"));
		}

		public void addElement(StringBuffer buf, Date date, Request request,
				Response response, long time) {
			if (currentDate != date) {
				synchronized (this) {
					if (currentDate != date) {
						currentDateString = dateFormatter.format(date);
						currentDate = date;
					}
				}
			}
			buf.append(currentDateString);
		}
	}

	protected class TimeElement implements AccessLogElement {
		private Date currentDate = new Date(0);

		private String currentTimeString = null;

		/**
		 * A date formatter to format a Date into a time in the format
		 * "kk:mm:ss" (kk is a 24-hour representation of the hour).
		 */
		private SimpleDateFormat timeFormatter = new SimpleDateFormat(
				"HH:mm:ss");

		public TimeElement() {
			timeFormatter.setTimeZone(TimeZone.getTimeZone("GMT"));
		}

		public void addElement(StringBuffer buf, Date date, Request request,
				Response response, long time) {
			if (currentDate != date) {
				synchronized (this) {
					if (currentDate != date) {
						currentTimeString = timeFormatter.format(date);
						currentDate = date;
					}
				}
			}
			buf.append(currentTimeString);
		}
	}

	protected class RequestHeaderElement implements AccessLogElement {
		private String header;

		public RequestHeaderElement(String header) {
			this.header = header;
		}

		public void addElement(StringBuffer buf, Date date, Request request,
				Response response, long time) {
			buf.append(wrap(request.getHeader(header)));
		}
	}

	protected class ResponseHeaderElement implements AccessLogElement {
		private String header;

		public ResponseHeaderElement(String header) {
			this.header = header;
		}

		public void addElement(StringBuffer buf, Date date, Request request,
				Response response, long time) {
			buf.append(wrap(response.getHeader(header)));
		}
	}

	protected class ServletContextElement implements AccessLogElement {
		private String attribute;

		public ServletContextElement(String attribute) {
			this.attribute = attribute;
		}

		public void addElement(StringBuffer buf, Date date, Request request,
				Response response, long time) {
			buf.append(wrap(request.getContext().getServletContext()
					.getAttribute(attribute)));
		}
	}

	protected class CookieElement implements AccessLogElement {
		private String name;

		public CookieElement(String name) {
			this.name = name;
		}

		public void addElement(StringBuffer buf, Date date, Request request,
				Response response, long time) {
			Cookie[] c = request.getCookies();
			for (int i = 0; c != null && i < c.length; i++) {
				if (name.equals(c[i].getName())) {
					buf.append(wrap(c[i].getValue()));
				}
			}
		}
	}

	/**
	 * write a specific response header - x-O(xxx)
	 */
	protected class ResponseAllHeaderElement implements AccessLogElement {
		private String header;

		public ResponseAllHeaderElement(String header) {
			this.header = header;
		}

		public void addElement(StringBuffer buf, Date date, Request request,
				Response response, long time) {
			if (null != response) {
				String[] values = response.getHeaderValues(header);
				if (values.length > 0) {
					StringBuffer buffer = new StringBuffer();
					for (int i = 0; i < values.length; i++) {
						String string = values[i];
						buffer.append(string);
						if (i + 1 < values.length)
							buffer.append(",");
					}
					buf.append(wrap(buffer.toString()));
					return;
				}
			}
			buf.append("-");
		}
	}

	protected class RequestAttributeElement implements AccessLogElement {
		private String attribute;

		public RequestAttributeElement(String attribute) {
			this.attribute = attribute;
		}

		public void addElement(StringBuffer buf, Date date, Request request,
				Response response, long time) {
			buf.append(wrap(request.getAttribute(attribute)));
		}
	}

	protected class SessionAttributeElement implements AccessLogElement {
		private String attribute;

		public SessionAttributeElement(String attribute) {
			this.attribute = attribute;
		}

		public void addElement(StringBuffer buf, Date date, Request request,
				Response response, long time) {
			HttpSession session = null;
			if (request != null) {
				session = request.getSession(false);
				if (session != null)
					buf.append(wrap(session.getAttribute(attribute)));
			}
		}
	}

	protected class RequestParameterElement implements AccessLogElement {
		private String parameter;

		public RequestParameterElement(String parameter) {
			this.parameter = parameter;
		}

		/**
		 * urlEncode the given string. If null or empty, return null.
		 */
		private String urlEncode(String value) {
			if (null == value || value.length() == 0) {
				return null;
			}
			return URLEncoder.encode(value);
		}

		public void addElement(StringBuffer buf, Date date, Request request,
				Response response, long time) {
			buf.append(wrap(urlEncode(request.getParameter(parameter))));
		}
	}

	protected class PatternTokenizer {
		private StringReader sr = null;
		private StringBuffer buf = new StringBuffer();
		private boolean ended = false;
		private boolean subToken;
		private boolean parameter;

		public PatternTokenizer(String str) {
			sr = new StringReader(str);
		}

		public boolean hasSubToken() {
			return subToken;
		}

		public boolean hasParameter() {
			return parameter;
		}

		public String getToken() throws IOException {
			if (ended)
				return null;

			String result = null;
			subToken = false;
			parameter = false;

			int c = sr.read();
			while (c != -1) {
				switch (c) {
				case ' ':
					result = buf.toString();
					buf = new StringBuffer();
					buf.append((char) c);
					return result;
				case '-':
					result = buf.toString();
					buf = new StringBuffer();
					subToken = true;
					return result;
				case '(':
					result = buf.toString();
					buf = new StringBuffer();
					parameter = true;
					return result;
				case ')':
					result = buf.toString();
					buf = new StringBuffer();
					break;
				default:
					buf.append((char) c);
				}
				c = sr.read();
			}
			ended = true;
			if (buf.length() != 0) {
				return buf.toString();
			} else {
				return null;
			}
		}

		public String getParameter() throws IOException {
			String result;
			if (!parameter) {
				return null;
			}
			parameter = false;
			int c = sr.read();
			while (c != -1) {
				if (c == ')') {
					result = buf.toString();
					buf = new StringBuffer();
					return result;
				}
				buf.append((char) c);
				c = sr.read();
			}
			return null;
		}

		public String getWhiteSpaces() throws IOException {
			if (isEnded())
				return "";
			StringBuffer whiteSpaces = new StringBuffer();
			if (buf.length() > 0) {
				whiteSpaces.append(buf);
				buf = new StringBuffer();
			}
			int c = sr.read();
			while (Character.isWhitespace((char) c)) {
				whiteSpaces.append((char) c);
				c = sr.read();
			}
			if (c == -1) {
				ended = true;
			} else {
				buf.append((char) c);
			}
			return whiteSpaces.toString();
		}

		public boolean isEnded() {
			return ended;
		}

		public String getRemains() throws IOException {
			StringBuffer remains = new StringBuffer();
			for (int c = sr.read(); c != -1; c = sr.read()) {
				remains.append((char) c);
			}
			return remains.toString();
		}

	}

	protected AccessLogElement[] createLogElements() {
		if (log.isDebugEnabled()) {
			log.debug("decodePattern, pattern =" + pattern);
		}
		List<AccessLogElement> list = new ArrayList<AccessLogElement>();

		PatternTokenizer tokenizer = new PatternTokenizer(pattern);
		try {

			// Ignore leading whitespace.
			tokenizer.getWhiteSpaces();

			if (tokenizer.isEnded()) {
				log.info("pattern was just empty or whitespace");
				return null;
			}

			String token = tokenizer.getToken();
			while (token != null) {
				if (log.isDebugEnabled()) {
					log.debug("token = " + token);
				}
				AccessLogElement element = getLogElement(token, tokenizer);
				if (element == null) {
					break;
				}
				list.add(element);
				String whiteSpaces = tokenizer.getWhiteSpaces();
				if (whiteSpaces.length() > 0) {
					list.add(new StringElement(whiteSpaces));
				}
				if (tokenizer.isEnded()) {
					break;
				}
				token = tokenizer.getToken();
			}
			if (log.isDebugEnabled()) {
				log.debug("finished decoding with element size of: "
						+ list.size());
			}
			return (AccessLogElement[]) list.toArray(new AccessLogElement[0]);
		} catch (IOException e) {
			log.error("parse error", e);
			return null;
		}
	}

	protected AccessLogElement getLogElement(String token,
			PatternTokenizer tokenizer) throws IOException {
		if ("date".equals(token)) {
			return new DateElement();
		} else if ("time".equals(token)) {
			if (tokenizer.hasSubToken()) {
				String nextToken = tokenizer.getToken();
				if ("taken".equals(nextToken)) {
					return new ElapsedTimeElement(false);
				}
			} else {
				return new TimeElement();
			}
		} else if ("bytes".equals(token)) {
			return new ByteSentElement(true);
		} else if ("cached".equals(token)) {
			/* I don't know how to evaluate this! */
			return new StringElement("-");
		} else if ("c".equals(token)) {
			String nextToken = tokenizer.getToken();
			if ("ip".equals(nextToken)) {
				return new RemoteAddrElement();
			} else if ("dns".equals(nextToken)) {
				return new HostElement();
			}
		} else if ("s".equals(token)) {
			String nextToken = tokenizer.getToken();
			if ("ip".equals(nextToken)) {
				return new LocalAddrElement();
			} else if ("dns".equals(nextToken)) {
				return new AccessLogElement() {
					public void addElement(StringBuffer buf, Date date,
							Request request, Response response, long time) {
						String value;
						try {
							value = InetAddress.getLocalHost().getHostName();
						} catch (Throwable e) {
							value = "localhost";
						}
						buf.append(value);
					}
				};
			}
		} else if ("cs".equals(token)) {
			return getClientToServerElement(tokenizer);
		} else if ("sc".equals(token)) {
			return getServerToClientElement(tokenizer);
		} else if ("sr".equals(token) || "rs".equals(token)) {
			return getProxyElement(tokenizer);
		} else if ("x".equals(token)) {
			return getXParameterElement(tokenizer);
		}
		log.error("unable to decode with rest of chars starting: " + token);
		return null;
	}

	protected AccessLogElement getClientToServerElement(
			PatternTokenizer tokenizer) throws IOException {
		if (tokenizer.hasSubToken()) {
			String token = tokenizer.getToken();
			if ("method".equals(token)) {
				return new MethodElement();
			} else if ("uri".equals(token)) {
				if (tokenizer.hasSubToken()) {
					token = tokenizer.getToken();
					if ("stem".equals(token)) {
						return new RequestURIElement();
					} else if ("query".equals(token)) {
						return new AccessLogElement() {
							public void addElement(StringBuffer buf, Date date,
									Request request, Response response,
									long time) {
								String query = request.getQueryString();
								if (query != null) {
									buf.append(query);
								} else {
									buf.append('-');
								}
							}
						};
					}
				} else {
					return new AccessLogElement() {
						public void addElement(StringBuffer buf, Date date,
								Request request, Response response, long time) {
							String query = request.getQueryString();
							if (query == null) {
								buf.append(request.getRequestURI());
							} else {
								buf.append(request.getRequestURI());
								buf.append('?');
								buf.append(request.getQueryString());
							}
						}
					};
				}
			}
		} else if (tokenizer.hasParameter()) {
			String parameter = tokenizer.getParameter();
			if (parameter == null) {
				log.error("No closing ) found for in decode");
				return null;
			}
			return new RequestHeaderElement(parameter);
		}
		log.error("The next characters couldn't be decoded: "
				+ tokenizer.getRemains());
		return null;
	}

	protected AccessLogElement getServerToClientElement(
			PatternTokenizer tokenizer) throws IOException {
		if (tokenizer.hasSubToken()) {
			String token = tokenizer.getToken();
			if ("status".equals(token)) {
				return new HttpStatusCodeElement();
			} else if ("comment".equals(token)) {
				return new StringElement("?");
			}
		} else if (tokenizer.hasParameter()) {
			String parameter = tokenizer.getParameter();
			if (parameter == null) {
				log.error("No closing ) found for in decode");
				return null;
			}
			return new ResponseHeaderElement(parameter);
		}
		log.error("The next characters couldn't be decoded: "
				+ tokenizer.getRemains());
		return null;
	}

	protected AccessLogElement getProxyElement(PatternTokenizer tokenizer)
			throws IOException {
		String token = null;
		if (tokenizer.hasSubToken()) {
			token = tokenizer.getToken();
			return new StringElement("-");
		} else if (tokenizer.hasParameter()) {
			tokenizer.getParameter();
			return new StringElement("-");
		}
		log.error("The next characters couldn't be decoded: " + token);
		return null;
	}

	protected AccessLogElement getXParameterElement(PatternTokenizer tokenizer)
			throws IOException {
		if (!tokenizer.hasSubToken()) {
			log
					.error("x param in wrong format. Needs to be 'x-#(...)' read the docs!");
			return null;
		}
		String token = tokenizer.getToken();
		if (!tokenizer.hasParameter()) {
			log
					.error("x param in wrong format. Needs to be 'x-#(...)' read the docs!");
			return null;
		}
		String parameter = tokenizer.getParameter();
		if (parameter == null) {
			log.error("No closing ) found for in decode");
			return null;
		}
		if ("A".equals(token)) {
			return new ServletContextElement(parameter);
		} else if ("C".equals(token)) {
			return new CookieElement(parameter);
		} else if ("R".equals(token)) {
			return new RequestAttributeElement(parameter);
		} else if ("S".equals(token)) {
			return new SessionAttributeElement(parameter);
		} else if ("H".equals(token)) {
			return getServletRequestElement(parameter);
		} else if ("P".equals(token)) {
			return new RequestParameterElement(parameter);
		} else if ("O".equals(token)) {
			return new ResponseAllHeaderElement(parameter);
		}
		log.error("x param for servlet request, couldn't decode value: "
				+ token);
		return null;
	}

	protected AccessLogElement getServletRequestElement(String parameter) {
		if ("authType".equals(parameter)) {
			return new AccessLogElement() {
				public void addElement(StringBuffer buf, Date date,
						Request request, Response response, long time) {
					buf.append(wrap(request.getAuthType()));
				}
			};
		} else if ("remoteUser".equals(parameter)) {
			return new AccessLogElement() {
				public void addElement(StringBuffer buf, Date date,
						Request request, Response response, long time) {
					buf.append(wrap(request.getRemoteUser()));
				}
			};
		} else if ("requestedSessionId".equals(parameter)) {
			return new AccessLogElement() {
				public void addElement(StringBuffer buf, Date date,
						Request request, Response response, long time) {
					buf.append(wrap(request.getRequestedSessionId()));
				}
			};
		} else if ("requestedSessionIdFromCookie".equals(parameter)) {
			return new AccessLogElement() {
				public void addElement(StringBuffer buf, Date date,
						Request request, Response response, long time) {
					buf.append(wrap(""
							+ request.isRequestedSessionIdFromCookie()));
				}
			};
		} else if ("requestedSessionIdValid".equals(parameter)) {
			return new AccessLogElement() {
				public void addElement(StringBuffer buf, Date date,
						Request request, Response response, long time) {
					buf.append(wrap("" + request.isRequestedSessionIdValid()));
				}
			};
		} else if ("contentLength".equals(parameter)) {
			return new AccessLogElement() {
				public void addElement(StringBuffer buf, Date date,
						Request request, Response response, long time) {
					buf.append(wrap("" + request.getContentLength()));
				}
			};
		} else if ("characterEncoding".equals(parameter)) {
			return new AccessLogElement() {
				public void addElement(StringBuffer buf, Date date,
						Request request, Response response, long time) {
					buf.append(wrap(request.getCharacterEncoding()));
				}
			};
		} else if ("locale".equals(parameter)) {
			return new AccessLogElement() {
				public void addElement(StringBuffer buf, Date date,
						Request request, Response response, long time) {
					buf.append(wrap(request.getLocale()));
				}
			};
		} else if ("protocol".equals(parameter)) {
			return new AccessLogElement() {
				public void addElement(StringBuffer buf, Date date,
						Request request, Response response, long time) {
					buf.append(wrap(request.getProtocol()));
				}
			};
		} else if ("scheme".equals(parameter)) {
			return new AccessLogElement() {
				public void addElement(StringBuffer buf, Date date,
						Request request, Response response, long time) {
					buf.append(request.getScheme());
				}
			};
		} else if ("secure".equals(parameter)) {
			return new AccessLogElement() {
				public void addElement(StringBuffer buf, Date date,
						Request request, Response response, long time) {
					buf.append(wrap("" + request.isSecure()));
				}
			};
		}
		log.error("x param for servlet request, couldn't decode value: "
				+ parameter);
		return null;
	}

}
